3D active edge silicon sensor testbeam studies

At a particle flux of 1015 neqcm-2, as will be already reached for the innermost layers of the LHC detectors, current silicon sensors reach the limits of their radiation hardness. At sLHC the radiation dose will increase by at least one order of magnitude. At these doses it becomes impossible to fully deplete the sensors. Since only the depleted part contributes to signal generation, the devices seize to operate. One possible solution are 3D detectors. Here the collecting diodes are not on top of the detector, but are grown into the bulk. This results in short electrodes that are at very small distances. Therefore, the depletion voltage becomes very low, allowing full depletion even at very high fluences, and the charge collection becomes very fast, while still taking advantage of the full 300 μm thickness of the silicon. 3D detectors with different electrode topologies were operated in a high energy particle beam at CERN. (orig.)